This is going to sound stupid, but it's a legitimate question:

>>94699333
There is this unspoken rule among villians that you do not distribute a hero while he is on the shitter as doing so would be a huge dickmove too bad even for them.

batman has a bat-toilet
iron-mans suit is designed for prolonged use and has provisions for waste disposal
flash can piss before you notice
supermans bladder of steel can hold it in for a long time
same for thor

>>94699411
I just imagine there's been more than one awkward moment in an ally where Batman and a hobo have locked eyes while he's taking a leak behind a dumpster

>>94699333
I guess they alter their body clock so they never have to take a piss while on the job.
For example, every morning I need to go to the bathroom after I wake up and before I go to work or in an hour my bladder will be close to exploding.

Batman has a jell-like substance that forms a diaper under his briefs which absorbs liquid.

This prevents any bladder spasms from wetting his suit.

As for solid matter, Batman has trained his body to shit only once a week. He does everything he can to take this shit at home, as shit becomes very hard and difficult to pass when left in the body for that long. A side effect of this method is anal seepage that comes out around the stool as it lays dormant in the body, something that the aforementioned gel takes care of.